Systems and methods for determining rotation angles

ABSTRACT

The present disclosure relates to systems and methods for determining rotation angles. The systems may perform the methods to: obtain a rotation speed of a radioactive scanning source in a CT scanner; obtain a plurality of original projection acquisition times corresponding to a plurality of projection samples, the plurality of projection samples being associated with rotation of the radioactive scanning source; determine a plurality of original rotation angles corresponding to the plurality of projection samples based on the plurality of original projection acquisition times and the rotation speed of the radioactive scanning source; and determine a plurality of modified rotation angles corresponding to the plurality of projection samples by modifying the plurality of original rotation angles.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/099347 filed on Aug. 28, 2017, the entire contents of whichare hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure generally relates to image reconstruction ofcomputed tomography (CT), and more specifically, relates to methods andsystems to determine rotation angles of CT.

BACKGROUND

Computed tomography (CT) has been widely used in medical diagnosis. CTis a technology that makes use of computer-processed combinations ofX-ray images taken from different angles of an object to producecross-sectional images. Angle information (e.g., rotation angle) of CTmay be important in CT image reconstruction. During a CT scan, a CTscanner may acquire a plurality of projection samples to keep track ofrotation angles of a radioactive scanning source. The CT scanner mayrecord a plurality of projection acquisition times for the plurality ofprojection samples. However, because of a system error of the CT scanner(e.g., an error of hardware of the CT scanner, an error of datatransmission of the CT scanner, etc.), there may be an error in therecorded projection acquisition times, which may cause an error in thedetermination of rotation angles. The error in the rotation angles maycause artifacts (e.g., staircase artifacts) in a reconstructed CT image.Therefore, it is desirable to provide systems and methods fordetermining rotation angles to reduce/eliminate the error in therecorded projection acquisition times.

SUMMARY

Additional features will be set forth in part in the description whichfollows, and in part will become apparent to those skilled in the artupon examination of the following and the accompanying drawings or maybe learned by production or operation of the examples. The features ofthe present disclosure may be realized and attained by practice or useof various aspects of the methodologies, instrumentalities andcombinations set forth in the detailed examples discussed below.

According to a first aspect of the present disclosure, a system mayinclude one or more storage media and one or more processors configuredto communicate with the one or more storage media. The one or morestorage media may include a set of instructions for analyzing data froma computer tomography (CT) scanner. When the one or more processorsexecuting the set of instructions, the one or more processors may bedirected to perform one or more of the following operations. The one ormore processors may obtain a rotation speed of a radioactive scanningsource in the CT scanner. The one or more processors may obtain aplurality of original projection acquisition times corresponding to aplurality of projection samples, the plurality of projection samplesbeing associated with rotation of the radioactive scanning source. Theone or more processors may determine a plurality of original rotationangles corresponding to the plurality of projection samples based on theplurality of original projection acquisition times and the rotationspeed of the radioactive scanning source. The one or more processors maydetermine a plurality of modified rotation angles corresponding to theplurality of projection samples by modifying the plurality of originalrotation angles.

In some embodiments, the one or more processors may determine one ormore interpolation rotation angles based on the plurality of modifiedrotation angles.

In some embodiments, to determine the one or more interpolation rotationangles based on the plurality of modified rotation angles, the one ormore processors may obtain one or more view acquisition times associatedwith one or more view samples, the one or more view samples beingassociated with X-rays of the CT scanner. The one or more processors maydetermine the one or more interpolation rotation angles based on the oneor more view acquisition times and the plurality of modified rotationangles.

In some embodiments, to determine the plurality of modified rotationangles corresponding to the plurality of projection samples by modifyingthe plurality of original rotation angles, the one or more processorsmay obtain a plurality of standard rotation angles corresponding to theplurality of projection samples. The one or more processors may comparethe plurality of original rotation angles with the plurality ofcorresponding standard rotation angles, respectively. The one or moreprocessors may modify the plurality of original rotation angles based onthe plurality of standard rotation angles and the comparison.

In some embodiments, to obtain the plurality of standard rotation anglescorresponding to the plurality of projection samples, the one or moreprocessors may obtain a sample number of the plurality of projectionsamples. The one or more processors may determine, based on the samplenumber of the plurality of projection samples, a standard angledifference corresponding to any two neighboring projection samplesarranged in time order. The one or more processors may determine theplurality of standard rotation angles based on the standard angledifference.

In some embodiments, to obtain the plurality of standard rotation anglescorresponding to the plurality of projection samples, the one or moreprocessors may obtain a sample number of the plurality of projectionsamples. The one or more processors may determine, based on the samplenumber of the plurality of projection samples and the rotation speed ofthe radioactive scanning source, a standard time differencecorresponding to any two neighboring projection samples arranged in timeorder. The one or more processors may determine a standard angledifference corresponding to any two neighboring projection samplesarranged in time order based on the rotation speed of the radioactivescanning source and the standard time difference. The one or moreprocessors may determine the plurality of standard rotation angles basedon the standard angle difference.

In some embodiments, to determine the plurality of modified rotationangles corresponding to the plurality of projection samples by modifyingthe plurality of original rotation angles, the one or more processorsmay obtain a standard angle difference value corresponding to any twoneighboring projection samples of the plurality of projection samplesarranged in time order. The one or more processors may determine aplurality of original difference values each of which corresponds to twoneighbor original rotation angles of the plurality of original rotationangles arranging in order of time. The one or more processors maycompare the plurality of the original difference values with thestandard difference value, respectively. The one or more processors maymodify the plurality of original difference values based on the standarddifference value and the comparison. The one or more processors maydetermine the plurality of modified rotation angles based on theplurality of modified difference values.

According to another aspect of the present disclosure, a system mayinclude one or more storage media and one or more processors configuredto communicate with the one or more storage media. The one or morestorage media may include a set of instructions for analyzing data froma computer tomography (CT) scanner. When the one or more processorsexecuting the set of instructions, the one or more processors may bedirected to perform one or more of the following operations. The one ormore processors may obtain a rotation speed of a radioactive scanningsource in the CT scanner. The one or more processors may obtain aplurality of original projection acquisition times corresponding to theplurality of projection samples, the plurality of projection samplesbeing associated with rotation of the radioactive scanning source. Theone or more processors may determine a plurality of modified projectionacquisition times corresponding to the plurality of projection samplesby modifying the plurality of original projection acquisition times. Theone or more processors may determine a plurality of modified rotationangles corresponding to the plurality of projection samples based on therotation speed of the radioactive scanning source and the plurality ofmodified projection acquisition times.

In some embodiments, the one or more processors may determine one ormore interpolation rotation angles based on the plurality of modifiedrotation angles.

In some embodiments, to determine the one or more interpolation rotationangles based on the plurality of modified rotation angles, the one ormore may obtain one or more view acquisition times associated with oneor more view samples, the one or more view samples being associated withX-rays of the CT scanner. The one or more processors may determine theone or more interpolation rotation angles based on the one or more viewacquisition times and the plurality of modified rotation angles.

In some embodiments, to determine the plurality of modified projectionacquisition times, the one or more processors may obtain a plurality ofstandard projection acquisition times corresponding to the plurality ofprojection samples. The one or more processors may compare the pluralityof original projection acquisition times with the plurality ofcorresponding standard projection acquisition times, respectively. Theone or more processors may modify the plurality of original projectionacquisition times based on the plurality of standard projectionacquisition times and the comparison.

In some embodiments, to obtain the plurality of standard projectionacquisition times corresponding to the plurality of projection samples,the one or more processors may obtain a sample number of the pluralityof projection samples. The one or more processors may determine astandard time difference value corresponding to any two neighboringprojection samples of the plurality of projection samples arranged intime order based on the sample number of the plurality of projectionsamples and the rotation speed of the radioactive scanning source. Theone or more processors may determine the plurality of standardprojection acquisition times based on the standard time differencevalue.

In some embodiments, to determine the plurality of modified projectionacquisition times, the one or more processors may obtain a standard timedifference value corresponding to any two neighboring projection samplesof the plurality of projection samples arranged in time order. The oneor more processors may determine a plurality of original time differencevalues each of which corresponds to two neighbor original projectionacquisition times of the plurality of original projection acquisitiontimes. The one or more processors may compare the plurality of originaltime difference values with the standard time difference value,respectively. The one or more processors may modify the plurality oforiginal time difference values based on the standard time differencevalue and the comparison. The one or more processors may determine theplurality of modified projection acquisition times based on theplurality of modified time difference values.

According to yet another aspect of the present disclosure, a method mayinclude one or more of the following operations. One or more processorsmay obtain a rotation speed of a radioactive scanning source in a CTscanner. The one or more processors may obtain a plurality of originalprojection acquisition times corresponding to a plurality of projectionsamples, the plurality of projection samples being associated withrotation of the radioactive scanning source. The one or more processorsmay determine a plurality of original rotation angles corresponding tothe plurality of projection samples based on the plurality of originalprojection acquisition times and the rotation speed of the radioactivescanning source. The one or more processors may determine a plurality ofmodified rotation angles corresponding to the plurality of projectionsamples by modifying the plurality of original rotation angles.

According to yet another aspect of the present disclosure, a method mayinclude one or more of the following operations. One or more processorsmay obtain a rotation speed of a radioactive scanning source in a CTscanner. The one or more processors may obtain a plurality of originalprojection acquisition times corresponding to the plurality ofprojection samples, the plurality of projection samples being associatedwith rotation of the radioactive scanning source. The one or moreprocessors may determine a plurality of modified projection acquisitiontimes corresponding to the plurality of projection samples by modifyingthe plurality of original projection acquisition times. The one or moreprocessors may determine a plurality of modified rotation anglescorresponding to the plurality of projection samples based on therotation speed of the radioactive scanning source and the plurality ofmodified projection acquisition times.

According to yet another aspect of the present disclosure, a system maycomprise: a system information obtaining module configured to obtain arotation speed of a radioactive scanning source in a CT scanner; a timeobtaining module configured to obtain a plurality of original projectionacquisition times corresponding to a plurality of projection samples,the plurality of projection samples being associated with rotation ofthe radioactive scanning source; and a modification module configured todetermine a plurality of original rotation angles corresponding to theplurality of projection samples based on the plurality of originalprojection acquisition times and the rotation speed of the radioactivescanning source, and determine a plurality of modified rotation anglescorresponding to the plurality of projection samples by modifying theplurality of original rotation angles.

According to yet another aspect of the present disclosure, a system maycomprise: a system information obtaining module configured to obtain arotation speed of a radioactive scanning source in a CT scanner; a timeobtaining module configured to obtain a plurality of original projectionacquisition times corresponding to the plurality of projection samples,the plurality of projection samples being associated with rotation ofthe radioactive scanning source; and a modification module configured todetermine a plurality of modified projection acquisition timescorresponding to the plurality of projection samples by modifying theplurality of original projection acquisition times, and determine aplurality of modified rotation angles corresponding to the plurality ofprojection samples based on the rotation speed of the radioactivescanning source and the plurality of modified projection acquisitiontimes.

According to yet another aspect of the present disclosure, anon-transitory computer readable medium may comprise at least one set ofinstructions. The at least one set of instructions may be executed byone or more processors of a computer server. The one or more processorsmay obtain a rotation speed of a radioactive scanning source in a CTscanner. The one or more processors may obtain a plurality of originalprojection acquisition times corresponding to a plurality of projectionsamples, the plurality of projection samples being associated withrotation of the radioactive scanning source. The one or more processorsmay determine a plurality of original rotation angles corresponding tothe plurality of projection samples based on the plurality of originalprojection acquisition times and the rotation speed of the radioactivescanning source. The one or more processors may determine a plurality ofmodified rotation angles corresponding to the plurality of projectionsamples by modifying the plurality of original rotation angles.

According to yet another aspect of the present disclosure, anon-transitory computer readable medium may comprise at least one set ofinstructions. The at least one set of instructions may be executed byone or more processors of a computer server. The one or more processorsmay obtain a rotation speed of a radioactive scanning source in a CTscanner. The one or more processors may obtain a plurality of originalprojection acquisition times corresponding to the plurality ofprojection samples, the plurality of projection samples being associatedwith rotation of the radioactive scanning source. The one or moreprocessors may determine a plurality of modified projection acquisitiontimes corresponding to the plurality of projection samples by modifyingthe plurality of original projection acquisition times. The one or moreprocessors may determine a plurality of modified rotation anglescorresponding to the plurality of projection samples based on therotation speed of the radioactive scanning source and the plurality ofmodified projection acquisition times.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings. These embodiments are non-limiting exemplaryembodiments, in which like reference numerals represent similarstructures throughout the several views of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary CT systemaccording to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary computing device according to someembodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device according to someembodiments of the present disclosure;

FIG. 4 is a block diagram illustrating an exemplary processing engineaccording to some embodiments of the present disclosure;

FIG. 5 is a flowchart illustrating an exemplary process for determiningone or more new rotation angles according to some embodiments of thepresent disclosure;

FIG. 6 is a flowchart illustrating an exemplary process for performingmodification associated with a plurality of projection samples accordingto some embodiments of the present disclosure;

FIG. 7 is a flowchart illustrating an exemplary process for determiningmodified sample information according to some embodiments of the presentdisclosure; and

FIG. 8 is a flowchart illustrating an exemplary process for determiningone or more new rotation angles according to some embodiments of thepresent disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant disclosure. However, it should be apparent to those skilledin the art that the present disclosure may be practiced without suchdetails. In other instances, well-known methods, procedures, systems,components, and/or circuitry have been described at a relativelyhigh-level, without detail, in order to avoid unnecessarily obscuringaspects of the present disclosure. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. Thus, the present disclosure is not limitedto the embodiments shown, but to be accorded the widest scope consistentwith the claims.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise,”“comprises,” and/or “comprising,” “include,” “includes,” and/or“including,” when used in this specification, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

It will be understood that the term “system,” “engine,” “unit,”“module,” and/or “block” used herein are one method to distinguishdifferent components, elements, parts, section or assembly of differentlevel in ascending order. However, the terms may be displaced by otherexpression if they achieve the same purpose.

Generally, the word “module,” “unit,” or “block,” as used herein, refersto logic embodied in hardware or firmware, or to a collection ofsoftware instructions. A module, a unit, or a block described herein maybe implemented as software and/or hardware and may be stored in any typeof non-transitory computer-readable medium or other storage device. Insome embodiments, a software module/unit/block may be compiled andlinked into an executable program. It will be appreciated that softwaremodules can be callable from other modules/units/blocks or fromthemselves, and/or may be invoked in response to detected events orinterrupts. Software modules/units/blocks configured for execution oncomputing devices (e.g., the processor 210 as illustrated in FIG. 2) maybe provided on a computer-readable medium, such as a compact disc, adigital video disc, a flash drive, a magnetic disc, or any othertangible medium, or as a digital download (and can be originally storedin a compressed or installable format that needs installation,decompression, or decryption prior to execution). Such software code maybe stored, partially or fully, on a storage device of the executingcomputing device, for execution by the computing device. Softwareinstructions may be embedded in a firmware, such as an EPROM. It will befurther appreciated that hardware modules/units/blocks may be includedin connected logic components, such as gates and flip-flops, and/or canbe included of programmable units, such as programmable gate arrays orprocessors. The modules/units/blocks or computing device functionalitydescribed herein may be implemented as software modules/units/blocks,but may be represented in hardware or firmware. In general, themodules/units/blocks described herein refer to logicalmodules/units/blocks that may be combined with othermodules/units/blocks or divided into sub-modules/sub-units/sub-blocksdespite their physical organization or storage. The description may beapplicable to a system, an engine, or a portion thereof.

It will be understood that when a unit, engine, module or block isreferred to as being “on,” “connected to,” or “coupled to,” anotherunit, engine, module, or block, it may be directly on, connected orcoupled to, or communicate with the other unit, engine, module, orblock, or an intervening unit, engine, module, or block may be present,unless the context clearly indicates otherwise. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

These and other features, and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structure and the combination of parts and economies ofmanufacture, may become more apparent upon consideration of thefollowing description with reference to the accompanying drawings, allof which form a part of this disclosure. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration and description only and are not intended to limit thescope of the present disclosure. It is understood that the drawings arenot to scale.

Provided herein are systems and components for non-invasive imaging,such as for disease diagnosis or research purposes. In some embodiments,the imaging system may be a computed tomography (CT) system, an emissioncomputed tomography (ECT) system, a magnetic resonance imaging (MRI)system, an ultrasonography system, an X-ray photography system, apositron emission tomography (PET) system, or the like, or anycombination thereof.

For illustration purposes, the disclosure describes systems and methodsto determine rotation angles of CT for image reconstruction. During a CTscan, a CT scanner may acquire a plurality of projection samples to keeptrack of rotation angles of a radioactive scanning source. The CTscanner may record a plurality of projection acquisition times for theplurality of projection samples. The present disclosure provides systemsand methods that perform modification to reduce/eliminate the error inthe recorded projection acquisition times. Systems and methods in thisdisclosure may determine rotation angles based on the modification anddetermine one or more new rotation angles using a linear interpolationalgorithm based on the rotation angles.

The following description is provided to help better understanding theprocessing methods and/or systems. This is not intended to limit thescope the present disclosure. For persons having ordinary skills in theart, a certain amount of variations, changes, and/or modifications maybe deducted under the guidance of the present disclosure. Thosevariations, changes, and/or modifications do not depart from the scopeof the present disclosure.

FIG. 1 is a schematic diagrams illustrating an exemplary computedtomography (CT) system 100 according to some embodiments of the presentdisclosure. As shown in FIG. 1, the CT system 100 may include a CTscanner 110, a network 120, one or more terminals 130, a processingengine 140, and a database 150.

The CT scanner 110 may include a gantry 111, a detector 112, a detectingregion 113, a table 114, and a radioactive scanning source 115. Thegantry 111 may support the detector 112 and the radioactive scanningsource 115. A scanned object may be placed on the table 114 forscanning. The radioactive scanning source 115 may emit radioactive raysto the scanned object. The detector 112 may detect radiation events(e.g., gamma photons) emitted from the detecting region 113. In someembodiments, the detector 112 may include one or more detector units.The detector units may include a scintillation detector (e.g., a cesiumiodide detector), a gas detector, etc. The detector unit may be and/orinclude a single-row detector and/or a multi-rows detector.

The network 120 may include any suitable network that can facilitateexchange of information and/or data for the CT system 100. In someembodiments, one or more components of the CT system 100 (e.g., the CTscanner 110, the terminal 130, the processing engine 140, the database150, etc.) may communicate information and/or data with one or moreother components of the CT system 100 via the network 120. For example,the processing engine 140 may obtain information associated with theradioactive scanning source 115 from the CT scanner 110 via the network120. As another example, the processing engine 140 may obtain userinstructions from the terminal 130 via the network 120. The network 120may be and/or include a public network (e.g., the Internet), a privatenetwork (e.g., a local area network (LAN), a wide area network (WAN)),etc.), a wired network (e.g., an Ethernet network), a wireless network(e.g., an 802.11 network, a Wi-Fi network, etc.), a cellular network(e.g., a Long Term Evolution (LTE) network), a frame relay network, avirtual private network (“VPN”), a satellite network, a telephonenetwork, routers, hubs, witches, server computers, and/or anycombination thereof. Merely by way of example, the network 120 mayinclude a cable network, a wireline network, a fiber-optic network, atelecommunications network, an intranet, a wireless local area network(WLAN), a metropolitan area network (MAN), a public telephone switchednetwork (PSTN), a Bluetooth™ network, a ZigBee™ network, a near fieldcommunication (NFC) network, or the like, or any combination thereof. Insome embodiments, the network 120 may include one or more network accesspoints. For example, the network 120 may include wired and/or wirelessnetwork access points such as base stations and/or internet exchangepoints through which one or more components of the CT system 100 may beconnected to the network 120 to exchange data and/or information.

The terminal(s) 130 may include a mobile device 130-1, a tablet computer130-2, a laptop computer 130-3, or the like, or any combination thereof.In some embodiments, the mobile device 130-1 may include a smart homedevice, a wearable device, a mobile device, a virtual reality device, anaugmented reality device, or the like, or any combination thereof. Insome embodiments, the smart home device may include a smart lightingdevice, a control device of an intelligent electrical apparatus, a smartmonitoring device, a smart television, a smart video camera, aninterphone, or the like, or any combination thereof. In someembodiments, the wearable device may include a bracelet, a footgear,eyeglasses, a helmet, a watch, clothing, a backpack, a smart accessory,or the like, or any combination thereof. In some embodiments, the mobiledevice may include a mobile phone, a personal digital assistance (PDA),a gaming device, a navigation device, a point of sale (POS) device, alaptop, a tablet computer, a desktop, or the like, or any combinationthereof. In some embodiments, the virtual reality device and/or theaugmented reality device may include a virtual reality helmet, virtualreality glasses, a virtual reality patch, an augmented reality helmet,augmented reality glasses, an augmented reality patch, or the like, orany combination thereof. For example, the virtual reality device and/orthe augmented reality device may include a Google Glass™, an OculusRift™, a Hololens™, a Gear VR™, etc. In some embodiments, theterminal(s) 130 may be part of the processing engine 140.

The processing engine 140 may process data and/or information obtainedfrom the CT scanner 110, the terminal 130, and/or the database 150. Forexample, the processing engine 140 may obtain information associatedwith the radioactive scanning source 115 and modify the informationassociated with the radioactive scanning source 115. In someembodiments, the processing engine 140 may be a single server or aserver group. The server group may be centralized or distributed. Insome embodiments, the processing engine 140 may be local or remote. Forexample, the processing engine 140 may access information and/or datastored in the CT scanner 110, the terminal 130, and/or the database 150via the network 120. As another example, the processing engine 140 maybe directly connected to the CT scanner 110, the terminal 130 and/or thedatabase 150 to access stored information and/or data. In someembodiments, the processing engine 140 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof. In some embodiments, the processing engine 140 maybe implemented by a computing device 200 having one or more componentsas illustrated in FIG. 2.

The database 150 may store data, instructions, and/or any otherinformation. In some embodiments, the database 150 may store dataobtained from the terminal 130 and/or the processing engine 140. In someembodiments, the database 150 may store data and/or instructions thatthe processing engine 140 and/or the terminal 130 may execute or use toperform exemplary methods described in the present disclosure. In someembodiments, the database 150 may include a mass storage, a removablestorage, a volatile read-and-write memory, a read-only memory (ROM), orthe like, or any combination thereof. Exemplary mass storage may includea magnetic disk, an optical disk, a solid-state drive, etc. Exemplaryremovable storage may include a flash drive, a floppy disk, an opticaldisk, a memory card, a zip disk, a magnetic tape, etc. Exemplaryvolatile read-and-write memory may include a random access memory (RAM).Exemplary RAM may include a dynamic RAM (DRAM), a double date ratesynchronous dynamic RAM (DDR SDRAM), a static RAM (SRAM), a thyristorRAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc. Exemplary ROM mayinclude a mask ROM (MROM), a programmable ROM (PROM), an erasableprogrammable ROM (EPROM), an electrically erasable programmable ROM(EEPROM), a compact disk ROM (CD-ROM), and a digital versatile disk ROM,etc. In some embodiments, the database 150 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof.

In some embodiments, the database 150 may be connected to the network120 to communicate with one or more other components in the CT system100 (e.g., the processing engine 140, the terminal 130, etc.). One ormore components in the CT system 100 may access the data or instructionsstored in the database 150 via the network 120. In some embodiments, thedatabase 150 may be directly connected to or communicate with one ormore other components in the CT system 100 (e.g., the CT scanner 110,the processing engine 140, the terminal 130, etc.). In some embodiments,the database 150 may be part of the processing engine 140.

FIG. 2 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary computing device 200 on which theprocessing engine 140 may be implemented according to some embodimentsof the present disclosure. As illustrated in FIG. 2, the computingdevice 200 may include a processor 210, a storage 220, an input/output(I/O) 230, and a communication port 240.

The processor 210 may execute computer instructions (e.g., program code)and perform functions of the processing engine 140 in accordance withtechniques described herein. The computer instructions may include, forexample, routines, programs, objects, components, data structures,procedures, modules, and functions, which perform particular functionsdescribed herein. For example, the processor 210 may process informationassociated with the radioactive scanning source 115 obtained from the CTscanner 110, the terminal 130, the database 150, and/or any othercomponent of the CT system 100. In some embodiments, the processor 210may include one or more hardware processors, such as a microcontroller,a microprocessor, a reduced instruction set computer (RISC), anapplication specific integrated circuits (ASICs), anapplication-specific instruction-set processor (ASIP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a physicsprocessing unit (PPU), a microcontroller unit, a digital signalprocessor (DSP), a field programmable gate array (FPGA), an advancedRISC machine (ARM), a programmable logic device (PLD), any circuit orprocessor capable of executing one or more functions, or the like, orany combinations thereof.

Merely for illustration, only one processor is described in thecomputing device 200. However, it should be noted that the computingdevice 200 in the present disclosure may also include multipleprocessors, thus operations and/or method steps that are performed byone processor as described in the present disclosure may also be jointlyor separately performed by the multiple processors. For example, if inthe present disclosure the processor of the computing device 200executes both step A and step B, it should be understood that step A andstep B may also be performed by two or more different processors jointlyor separately in the computing device 200 (e.g., a first processorexecutes step A and a second processor executes step B, or the first andsecond processors jointly execute steps A and B).

The storage 220 may store data/information obtained from the CT scanner110, the terminal 130, the database 150, and/or any other component ofthe CT system 100. In some embodiments, the storage 220 may include amass storage, a removable storage, a volatile read-and-write memory, aread-only memory (ROM), or the like, or any combination thereof. Forexample, the mass storage may include a magnetic disk, an optical disk,a solid-state drives, etc. The removable storage may include a flashdrive, a floppy disk, an optical disk, a memory card, a zip disk, amagnetic tape, etc. The volatile read-and-write memory may include arandom access memory (RAM). The RAM may include a dynamic RAM (DRAM), adouble date rate synchronous dynamic RAM (DDR SDRAM), a static RAM(SRAM), a thyristor RAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc.The ROM may include a mask ROM (MROM), a programmable ROM (PROM), anerasable programmable ROM (EPROM), an electrically erasable programmableROM (EEPROM), a compact disk ROM (CD-ROM), and a digital versatile diskROM, etc. In some embodiments, the storage 220 may store one or moreprograms and/or instructions to perform exemplary methods described inthe present disclosure. For example, the storage 220 may store a programfor the processing engine 140 for determining modified informationassociated with the radioactive scanning source 115 and determining newrotation angles associated with the radioactive scanning source 115.

The I/O 230 may input and/or output signals, data, information, etc. Insome embodiments, the I/O 230 may enable a user interaction with theprocessing engine 140. In some embodiments, the I/O 230 may include aninput device and an output device. Examples of the input device mayinclude a keyboard, a mouse, a touch screen, a microphone, or the like,or a combination thereof. Examples of the output device may include adisplay device, a loudspeaker, a printer, a projector, or the like, or acombination thereof. Examples of the display device may include a liquidcrystal display (LCD), a light-emitting diode (LED)-based display, aflat panel display, a curved screen, a television device, a cathode raytube (CRT), a touch screen, or the like, or a combination thereof.

The communication port 240 may be connected to a network (e.g., thenetwork 120) to facilitate data communications. The communication port240 may establish connections between the processing engine 140 and theCT scanner 110, the terminal 130, and/or the database 150. Theconnection may be a wired connection, a wireless connection, any othercommunication connection that can enable data transmission and/orreception, and/or any combination of these connections. The wiredconnection may include, for example, an electrical cable, an opticalcable, a telephone wire, or the like, or any combination thereof. Thewireless connection may include, for example, a Bluetooth™ link, aWi-Fi™ link, a WiMax™ link, a WLAN link, a ZigBee link, a mobile networklink (e.g., 3G, 4G, 5G, etc.), or the like, or a combination thereof. Insome embodiments, the communication port 240 may be and/or include astandardized communication port, such as RS232, RS485, etc. In someembodiments, the communication port 240 may be a specially designedcommunication port. For example, the communication port 240 may bedesigned in accordance with the digital imaging and communications inmedicine (DICOM) protocol.

FIG. 3 is a schematic diagram illustrating exemplary hardware and/orsoftware components of an exemplary mobile device 300 on which theterminal 130 may be implemented according to some embodiments of thepresent disclosure. As illustrated in FIG. 3, the mobile device 300 mayinclude a communication platform 310, a display 320, a graphicprocessing unit (GPU) 330, a central processing unit (CPU) 340, an I/O350, a memory 360, and a storage 390. In some embodiments, any othersuitable component, including but not limited to a system bus or acontroller (not shown), may also be included in the mobile device 300.In some embodiments, a mobile operating system 370 (e.g., iOS™,Android™, Windows Phone™ etc.) and one or more applications 380 may beloaded into the memory 360 from the storage 390 in order to be executedby the CPU 340. The applications 380 may include a browser or any othersuitable mobile apps for receiving and rendering information relating toimage processing or other information from the processing engine 140.User interactions with the information stream may be achieved via theI/O 350 and provided to the processing engine 140 and/or othercomponents of the CT system 100 via the network 120.

To implement various modules, units, and their functionalities describedin the present disclosure, computer hardware platforms may be used asthe hardware platform(s) for one or more of the elements describedherein. A computer with user interface elements may be used to implementa personal computer (PC) or any other type of work station or terminaldevice. A computer may also act as a server if appropriately programmed.

FIG. 4 is a block diagram illustrating an exemplary processing engine140 according to some embodiments of the present disclosure. Theprocessing engine 140 may include a system information obtaining module410, a time obtaining module 420, a modification module 430, and anangle determination module 440.

The system information obtaining module 410 may obtain systeminformation. In some embodiments, the system information may refer toinformation associated with one or more components of the CT scanner 110such as the gantry 111, the detector 112, the table 114, and theradioactive scanning source 115, etc. In a CT scan, the radioactivescanning source 115 may emit X-rays to a scanned object located in thetable 114. The X-rays may pass through the scanned object and mayattenuate during the passing process. After passing through the scannedobject, the attenuated X-rays may be detected by the detector 112.During the CT scan, the radioactive scanning source 115 may rotatearound the scanned object with the gantry 111 at a constant orapproximately constant speed. Because the radioactive scanning source115 is fixed on the gantry 111, the rotation speed of the gantry 111 maybe equal to or approximately equal to the rotation speed of theradioactive scanning source 115. During the CT scan, the CT scanner 110may acquire a plurality of projection samples to keep track of rotationangles of the radioactive scanning source 115. Based on the CT scan, thesystem information obtaining module 410 may obtain the systeminformation including a rotation speed of the gantry 111/the radioactivescanning source 115 and/or a sample number of projection samplesacquired in a time period (e.g., a period for the radioactive scanningsource 115 to go around for one rotation). Before the CT scan, a user ofthe CT system 100 (e.g., a doctor or a CT operator) may set the systeminformation. For example, the user may set the rotation speed of theradioactive scanning source 115 as 2 rotations per second (4π/s), andset the sample number of projection samples acquired in a period for theradioactive scanning source 115 to go around for one rotation as 50. Theuser may set the system information through the processing engine 140(e.g., the I/O 230) and/or the terminal 130 (e.g., the I/O 350). Thesystem information set by the user may be stored in the database 150and/or a storage device (e.g., the storage 220 of the processing engine140, the storage 390 of the terminal 130, the memory 360 of the terminal130, etc.). The system information obtaining module 410 may access thedatabase 150 and/or the storage device to obtain the system information.

The time obtaining module 420 may obtain a plurality of originalprojection acquisition times corresponding to a plurality of projectionsamples. In some embodiments, the CT scanner 110 may record an originalprojection acquisition time for a projection sample. For example, the CTscanner 110 may add a time stamp to the projection sample. The CTscanner 110 may store the plurality of projection acquisition times inthe database 150 and/or the storage device (e.g., the storage 220 of theprocessing engine 140, the storage 390 of the terminal 130, the memory360 of the terminal 130, etc.). The time obtaining module 420 may accessthe database 150 and/or the storage device to obtain the plurality oforiginal projection acquisition times.

The modification module 430 may perform modification associated with theplurality of projection samples based on the system information and theplurality of original projection acquisition times. The originalprojection acquisition time may be used to determine a rotation angle ofthe radioactive scanning source 115 corresponding to the projectionsample. The rotation angle of the radioactive scanning source 115 mayrefer to an angle between a location of the radioactive scanning source115 at a start time of the CT scan and a location of the radioactivescanning source 115 at a projection acquisition time. Rotation angles ofthe radioactive scanning source 115 may be important for CT imagereconstruction. However, because of a system error of the CT scanner 110(e.g., an error of hardware of the CT scanner 110, an error of datatransmission of the CT scanner 110, etc.), there may be an error in theoriginal projection acquisition time recorded by the CT scanner 110,which may cause an error in the determination of the rotation angle. Themodification module 430 may perform modification associated with theprojection samples to reduce/eliminate the error in the originalprojection acquisition times.

The angle determination module 440 may determine one or more newrotation angles (e.g., also referred to as interpolation rotationangles) based on the modification. In some embodiments, in the CT scan,the detector 112 may perform a plurality of view samples to keep trackof the attenuation of X-rays. In the CT scan, the sample number ofprojection samples may be less than the sample number of view samples,and the number of rotation angles corresponding to the projectionsamples may be fewer than the sample number of view samples. The angledetermination module 440 may determine one or more new rotation anglesto make the total number of the rotation angles corresponding to theprojection samples, and the new rotation angles equal to the samplenumber of the view samples. For example, in a period for the radioactivescanning source 115 to go around for one rotation, the detector 112 mayacquire 2400 view samples, and the CT scanner 110 may acquire 300projection samples. The angle determination module 440 may determine2100 new rotation angles to match the sample number of view samples.

In some embodiments, one or more modules illustrated in FIG. 4 may beimplemented in at least part of the exemplary CT system as illustratedin FIG. 1. For example, the system information obtaining 410, the timeobtaining 420, the modification module 430, and/or the angledetermination module 440 may be integrated into a console (not shown).Via the console, a user may set parameters for scanning an object,controlling processes of determining rotation angles, controllingparameters for reconstruction of an image, viewing reconstructed images,etc. In some embodiments, the console may be implemented via theprocessing engine 140 and/or the terminal 130.

The modules in the processing engine 140 may be connected to orcommunicate with each other via a wired connection or a wirelessconnection. The wired connection may include a metal cable, an opticalcable, a hybrid cable, or the like, or any combination thereof. Thewireless connection may include a Local Area Network (LAN), a Wide AreaNetwork (WAN), a Bluetooth, a ZigBee, a Near Field Communication (NFC),or the like, or any combination thereof. Two or more of the modules maybe combined as a single module, and any one of the modules may bedivided into two or more units. For example, the system informationobtaining module 410 may be integrated in the time obtaining module 420as a single module which may both obtain the system information and theprojection acquisition time.

It should be noted that the above description is merely provided for thepurposes of illustration, and not intended to limit the scope of thepresent disclosure. For persons having ordinary skills in the art,multiple variations and modifications may be made under the teachings ofthe present disclosure. However, those variations and modifications donot depart from the scope of the present disclosure. For example, theprocessing engine 140 may further include a storage module (not shown inFIG. 4). The storage module may be configured to store data generatedduring any process performed by any component of in the processingengine 140. As another example, each of components of the processingengine 140 may include a storage device. Additionally or alternatively,the components of the processing engine 140 may share a common storagedevice.

FIG. 5 is a flowchart illustrating an exemplary process/method 500 fordetermining one or more new rotation angles according to someembodiments of the present disclosure. In some embodiments, theprocess/method 500 may be implemented in the system 100 illustrated inFIG. 1. For example, the process/method 500 may be stored in thedatabase 150 and/or the storage device (e.g., the storage 220, thestorage 390, the memory 360, etc.) as a form of instructions, andinvoked and/or executed by the processing engine 140 (e.g., theprocessor 210 of the processing engine 140, or one or more modules inthe processing engine 140 illustrated in FIG. 4) and/or the terminal 130(e.g., the GUP 330 of the terminal 130, or the CUP 340 of the terminal130). The operations of the illustrated process/method presented beloware intended to be illustrative. In some embodiments, the process/method500 may be accomplished with one or more additional operations notdescribed, and/or without one or more of the operations discussed.Additionally, the order in which the operations of the process/method500 as illustrated in FIG. 5 and described below is not intended to belimiting.

In 510, the system information obtaining module 410 may obtain systeminformation. The system information may include a rotation speed of theradioactive scanning source 115 and/or the sample number of projectionsamples in a time period (e.g., a period for the radioactive scanningsource 115 to go around for one rotation).

In 520, the time obtaining module 420 may obtain a plurality of originalprojection acquisition times corresponding to a plurality of projectionsamples. In some embodiments, the CT scanner 110 may record an originalprojection acquisition time for a projection sample. For example, the CTscanner 110 may add a time stamp to the projection sample. The CTscanner 110 may store the plurality of original projection acquisitiontimes in the database 150 and/or the storage device (e.g., the storage220 of the processing engine 140, the storage 390 of the terminal 130,the memory 360 of the terminal 130, etc.). The system informationobtaining module 410 may access the database 150 and/or the storagedevice (e.g., the storage 220 of the processing engine 140, the storage390 of the terminal 130, the memory 360 of the terminal 130, etc.) toobtain the plurality of original projection acquisition times.

In 530, the modification module 430 may perform modification associatedwith the plurality of projection samples based on the system informationand the plurality of original projection acquisition times. Themodification of the plurality of projection samples is to eliminate theeffect caused by the error in the original projection acquisition times.In some embodiments, the modification module 430 may performmodification on the original projection acquisition times. In someembodiments, the modification module 430 may determine originalintervals between each two neighboring projection samples based on theoriginal projection acquisition times and perform modification on theoriginal intervals. In some embodiments, the modification module 430 maydetermine original rotation angles corresponding to the projectionsamples based on the original projection acquisition times and performmodification on the original rotation angles. In some embodiments, themodification module 430 may determine original angle differences betweeneach two original rotation angles corresponding to two neighboringprojection samples and perform modification on the angle differences.The process of performing modification will be descried in detail inconnection with FIG. 6 and/or FIG. 7.

In 540, the angle determination module 440 may determine one or more newrotation angles based on the modification. In some embodiments, theangle determination module 440 may determine one or more modifiedrotation angles based on the modification and determine the one or morenew rotation angles based on the modified rotation angles. In someembodiments, a modified rotation angle may refer to a modified value ofan original rotation angle. A new rotation angle may refer to a rotationangle generated based on one or more modified rotation angles. In someembodiments, the method of determining the one or more new rotationangles may include interpolation, extrapolation, smoothing, regressionanalysis, the least square method, or the like, or any combinationthereof. Exemplary interpolation methods may include Lagrangeinterpolation, Newton interpolation, Hermite interpolation, piecewiseinterpolation, spline interpolation, linear interpolation, or the like,or a combination thereof. Exemplary extrapolation methods may includelinear extrapolation, polynomial extrapolation, conic extrapolation,French curve extrapolation, or the like, or a combination thereof.Exemplary regression analysis may include linear regression, nonlinearregression, multiple regression, logistic regression, partialregression, or the like, or a combination thereof. As an example, theangle determination module 440 may use a linear interpolation algorithmto determine the one or more new rotation angles (e.g., as will bedescried in detail in connection with FIG. 8).

In some embodiments, the processing engine 140 may perform step 510 andstep 520 in any order. The processing engine 140 may perform step 510before or after step 520. In some embodiments, the processing engine 140may perform step 510 and step 520 simultaneously.

FIG. 6 is a flowchart illustrating an exemplary process/method 600 forperforming modification associated with a plurality of projectionsamples according to some embodiments of the present disclosure. In someembodiments, the process/method 600 may be implemented in the system 100illustrated in FIG. 1. For example, the process/method 600 may be storedin the database 150 and/or the storage device (e.g., the storage 220,the storage 390, the memory 360, etc.) as a form of instructions, andinvoked and/or executed by the processing engine 140 (e.g., theprocessor 210 of the processing engine 140, or one or more modules inthe processing engine 140 illustrated in FIG. 4) and/or the terminal 130(e.g., the GUP 330 of the terminal 130, or the CUP 340 of the terminal130). The operations of the illustrated process/method presented beloware intended to be illustrative. In some embodiments, the process/method600 may be accomplished with one or more additional operations notdescribed, and/or without one or more of the operations discussed.Additionally, the order in which the operations of the process/method600 as illustrated in FIG. 6 and described below is not intended to belimiting. In some embodiments, step 530 illustrated in FIG. 5 may beperformed according to the process/method 600. In some embodiments, theprocess/method 600 may be used to determine modified sample informationassociated with one projection sample. In some embodiments, themodification module 430 may determine modified sample informationassociated with a plurality of projection samples based on theprocess/method 600 one by one or simultaneously.

In 605, the modification module 430 may determine standard sampleinformation associated with a projection sample based on the systeminformation. The standard sample information may include a standardprojection acquisition time of the projection sample, a standardrotation angle of the projection sample, a standard interval betweeneach two neighboring projection samples, a standard angle differencebetween each two neighboring projection samples, or the like, or anycombination thereof.

In some embodiments, the modification module 430 may determine thestandard interval based on the rotation speed of the radioactivescanning source 115 and the sample number of projection samples in atime period (e.g., a period for the radioactive scanning source 115 togo around for one rotation). For example, the user may set the rotationspeed of the radioactive scanning source 115 as 2 rotations per second(4π/s), and set the sample number of projection samples in a period forthe radioactive scanning source 115 to go around for one rotation as 50.The modification module 430 may determine the standard interval as 10milliseconds.

In some embodiments, the modification module 430 may determine thestandard projection acquisition time based on the standard interval. Forexample, the user may set the rotation speed of the radioactive scanningsource 115 as 2 rotations per second (4π/s), and set the sample numberof projection samples in a period for the radioactive scanning source115 to go around for one rotation as 50. The standard interval may be 10milliseconds based on the rotation speed of the radioactive scanningsource 115 and the sample number of projection samples in a period forthe radioactive scanning source 115 to go around for one rotation. Themodification module 430 may determine the standard projectionacquisition time by multiplying the standard interval by a sequencenumber of the projection sample. The sequence number of the projectionsample may refer to an order in which the projection sample is acquiredby the CT scanner 110 in the CT scan. For example, the sequence numberof 3 may indicate that the projection sample is the third projectionsample acquired by the CT scanner 110 in the CT scan, and themodification module 430 may determine the standard projectionacquisition time of the projection sample as 10×3=30 milliseconds.

In some embodiments, the modification module 430 may determine thestandard angle difference based on the rotation speed of the radioactivescanning source 115 and the sample number of projection samples in atime period (e.g., a period for the radioactive scanning source 115 togo around for one rotation). For example, the user may set the rotationspeed of the radioactive scanning source 115 as 2 rotations per second(4π/s), and set the sample number of projection samples in a period forthe radioactive scanning source 115 to go around for one rotation as 50.The modification module 430 may determine the standard interval as0.04π(≈0.1256).

In some embodiments, the modification module 430 may determine thestandard rotation angle based on the standard angle difference. Forexample, the user may set the rotation speed of the radioactive scanningsource 115 as 2 rotations per second (4π/s), and set the sample numberof projection samples in a period for the radioactive scanning source115 to go around for one rotation as 50. The standard angle differencemay be 0.04π based on the rotation speed of the radioactive scanningsource 115 and the sample number of projection samples in a period forthe radioactive scanning source 115 to go around for one rotation. Themodification module 430 may determine the standard rotation angle bymultiplying the standard angle difference by the sequence number of theprojection sample. For example, the sequence number of the projectionsample may be 3. The modification module 430 may determine the standardrotation angle of the projection sample as 0.047π×3=0.12π.

In some embodiments, the modification module 430 may determine thestandard rotation angle based on the standard projection acquisitiontime. Further, modification module 430 may determine the standardrotation angle by multiplying the standard projection acquisition timeby the rotation speed of the radioactive scanning source 115. Forexample, the user may set the rotation speed of the radioactive scanningsource 115 as 2 rotations per second (4π/s), and set the sample numberof projection samples in a period for the radioactive scanning source115 to go around for one rotation as 50. The sequence number of theprojection sample may be 3. The modification module 430 may determinethe standard projection acquisition time of the projection sample as 30milliseconds. The modification module 430 may determine the standardrotation angle of the projection sample as 4π×0.03=0.12π.

In 610, the modification module 430 may determine original sampleinformation associated with a projection sample based on an originalprojection acquisition time of the projection sample and the systeminformation. In some embodiments, the original sample information mayinclude an original rotation angle of the projection sample, theoriginal projection acquisition time of the projection sample, anoriginal interval between a neighboring projection sample of theprojection sample (e.g., a neighboring projection sample prior to theprojection sample or behind the projection sample), an original angledifference between a neighboring projection sample of the projectionsample (e.g., a neighboring projection sample prior to the projectionsample or behind the projection sample).

In some embodiments, the modification module 430 may determine theoriginal rotation angle based on the original projection acquisitiontime. Further, the modification module 430 may determine the originalrotation angle by multiplying the original projection acquisition timeby the rotation speed of the radioactive scanning source 115. Forexample, the user may set the rotation speed of the radioactive scanningsource 115 as 2 rotations per second (4π/s). The original projectionacquisition time of the projection sample may be 10 milliseconds. Themodification module 430 may determine the original rotation angle of theprojection sample as 0.047π.

In some embodiments, the modification module 430 may determine theoriginal angle difference based on the original interval or the originalrotation angle. For example, the modification module 430 may determinethe original angle difference by multiplying the original interval bythe rotation speed of radioactive scanning source 115. As anotherexample, the modification module 430 may determine the original angledifference by determining a difference between the original rotationangle and an original rotation angle of a neighboring projection sample(e.g., a neighboring projection sample prior to the projection sample orbehind the projection sample).

In 620, the modification module 430 may determine modified sampleinformation associated with the projection sample based on the standardsample information and the original sample information. The modifiedsample information may include a modified projection acquisition time, amodified rotation angle, a modified interval between a neighboringprojection sample of the projection sample (e.g., a neighboringprojection sample prior to the projection sample or behind theprojection sample), a modified angle difference between a neighboringprojection sample of the projection sample (e.g., a neighboringprojection sample prior to the projection sample or behind theprojection sample), or the like, or any combination thereof. Thedetermination of the modified sample information will be descried indetail in connection with FIG. 7.

FIG. 7 is a flowchart illustrating an exemplary process/method 700 fordetermining modified sample information according to some embodiments ofthe present disclosure. In some embodiments, the process/method 700 maybe implemented in the system 100 illustrated in FIG. 1. For example, theprocess/method 700 may be stored in the database 150 and/or the storagedevice (e.g., the storage 220, the storage 390, the memory 360, etc.) asa form of instructions, and invoked and/or executed by the processingengine 140 (e.g., the processor 210 of the processing engine 140, or oneor more modules in the processing engine 140 illustrated in FIG. 4)and/or the terminal 130 (e.g., the GUP 330 of the terminal 130, or theCUP 340 of the terminal 130). The operations of the illustratedprocess/method presented below are intended to be illustrative. In someembodiments, the process/method 700 may be accomplished with one or moreadditional operations not described, and/or without one or more of theoperations discussed. Additionally, the order in which the operations ofthe process/method 700 as illustrated in FIG. 7 and described below isnot intended to be limiting. In some embodiments, step 620 illustratedin FIG. 6 may be performed according to the process/method 700.

In 720, the modification module 430 may determine a difference valuebetween the original sample information and the standard sampleinformation. In some embodiments, the modification module 430 maydetermine a difference value between the original projection acquisitiontime and the standard projection acquisition time. In some embodiments,the modification module 430 may determine a difference value between theoriginal rotation angle and the standard rotation angle. In someembodiments, the modification module 430 may determine a differencevalue between the original interval and the standard interval. In someembodiments, the modification module 430 may determine a differencevalue between the original angle difference and the standard angledifference.

In 730, the modification module 430 may determine whether the absolutevalue of the difference value is greater than a threshold. The thresholdmay be the default setting of the system 100.

In 740, the modification module 430 may determine modified sampleinformation by modifying the original sample information based on thestandard sample information in response to the determination that theabsolute value of the difference value is greater than the threshold.For example, the standard projection acquisition time of the projectionsample may be 30 milliseconds. The original projection acquisition timeof the projection acquisition time may be 25 milliseconds. The absolutevalue of the difference value between the standard projectionacquisition time and the original projection acquisition time may be 5milliseconds that is greater than the threshold (e.g., 1 millisecond).The modification module 430 may determine the modified projectionacquisition time as 30 milliseconds.

As another example, the standard interval may be 10 milliseconds. Theoriginal interval may be 5 milliseconds. The absolute value of thedifference value between the standard interval and the original intervalmay be 5 milliseconds that is greater than the threshold (e.g., 1millisecond). The modification module 430 may determine the modifiedinterval as 10 milliseconds.

As still another example, the standard rotation angle of the projectionsample may be 0.12π. The original rotation angle of the projectionsample may be 0.1π. The absolute value of the difference value betweenthe standard rotation angle and the original rotation angle may be 0.02π(≈0.0628) that is greater than the threshold (e.g., 0.01). Themodification module 430 may determine the modified rotation angle as0.12π.

As still another example, the standard angle difference may be 0.04π.The original angle difference may be 0.02π. The absolute value of thedifference value between the standard angle difference and the originalangle difference may be 0.02π (≈0.0628) that is greater than thethreshold (e.g., 0.01). The modification module 430 may determine themodified angle difference as 0.04π.

In some embodiments, the modification module 430 may perform nomodification on the original sample information in response to thedetermination that the absolute value of the difference value is lessthan or equal to the threshold.

FIG. 8 is a flowchart illustrating an exemplary process/method fordetermining one or more new rotation angles according to someembodiments in the present disclosure. In some embodiments, theprocess/method 800 may be implemented in the system 100 illustrated inFIG. 1. For example, the process/method 800 may be stored in thedatabase 150 and/or the storage device (e.g., the storage 220, thestorage 390, the memory 360, etc.) as a form of instructions, andinvoked and/or executed by the processing engine 140 (e.g., theprocessor 210 of the processing engine 140, or one or more modules inthe processing engine 140 illustrated in FIG. 4) and/or the terminal 130(e.g., the GUP 330 of the terminal 130, or the CUP 340 of the terminal130). The operations of the illustrated process/method presented beloware intended to be illustrative. In some embodiments, the process/method800 may be accomplished with one or more additional operations notdescribed, and/or without one or more of the operations discussed.Additionally, the order in which the operations of the process/method800 as illustrated in FIG. 8 and described below is not intended to belimiting. In some embodiments, step 540 illustrated in FIG. 5 may beperformed according to the process/method 800.

In 810, the angle determination module 440 may obtain a plurality ofview acquisition times associated with a plurality of view samplesacquired during the CT scan. In some embodiments, in the CT scan, thedetector 112 may perform a plurality of view samples to keep track ofthe attenuation of X-rays. In some embodiments, the CT scanner 110 mayrecord a view acquisition time for a view sample. For example, the CTscanner 110 may add a time stamp to the view sample. The CT scanner 110may store the plurality of view acquisition times in the database 150and/or the storage device (e.g., the storage 220 of the processingengine 140, the storage 390 of the terminal 130, the memory 360 of theterminal 130, etc.). The angle determination module 440 may access thedatabase 150 and/or the storage device to obtain the plurality of viewacquisition times.

In 820, the angle determination module 440 may determine one or moremodified rotation angles based on the modification.

In some embodiments, the modification module 430 may determine modifiedprojection acquisition times by performing modification on the originalprojection acquisition times. The angle determination module 440 maydetermine the modified rotation angles based on the modified projectionacquisition times. For example, the angle determination module 440 maydetermine a modified rotation angle of a projection sample bymultiplying the modified projection acquisition time of the projectionsample by the rotation speed of the radioactive scanning source 115.

In some embodiments, the modification module 430 may determine modifiedintervals by performing modification on the original intervals. Theangle determination module 440 may determine the modified rotationangles based on the modified intervals. For example, the angledetermination module 440 may determine a modified projection acquisitiontime based on the modified interval by determining the sum of themodified interval and intervals associated with projection samples priorto the projection sample, and determine a modified rotation angle bymultiplying the modified projection acquisition time by the rotationspeed of the radioactive scanning source 115. As another example, theangle determination module 440 may determine a modified angle differenceby multiplying the modified interval by the rotation speed of theradioactive scanning source 115 and determine a modified rotation anglebased on the modified angle difference.

In some embodiments, the modification module 430 may determine modifiedangle differences by performing modification on the original angledifferences. The angle determination module 440 may determine themodified rotation angles based on the modified angle differences. Forexample, the angle determination module 440 may determine a modifiedrotation angle by determining the sum of the modified angle differenceand angle differences associated with projection samples prior to theprojection sample.

In 830, the angle determination module 440 may determine one or more newrotation angles based on the modified rotation angles and the pluralityof view acquisition times. For example, in the CT scan, the CT scanner110 may perform 4 view samples corresponding to 4 view acquisition timesof T₁, T₂, T₃, and T₄, respectively, and the CT scanner 110 may perform2 projections samples corresponding to 2 projection acquisition times ofT₁ and T₄, respectively. The angle determination module 440 maydetermine 2 new rotation angles corresponding to T₂ and T₃,respectively. The angle determination module 440 may determine the oneor more new rotation angles through a linear interpolation algorithm.For example, the angle determination module 440 may determine a newrotation angle between two rotation angles of two projection samplesthat are acquired in a same rotation of the radioactive scanning source115 based on Formula (1) below:

Angle(x)=alfa*Angle 1+(1−alfa)*Angle 2  (1)

wherein Angle (x) represents the new rotation angle; Angle 1 representsa rotation angle corresponding to a projection acquisition time prior toa new projection acquisition time corresponding to the new rotationangle; Angle 2 represents a rotation angle corresponding to a projectionacquisition time behind the new projection acquisition time; and alfamay be expressed as Formula (2) below:

alfa=(Time 2−Time x)/(Time 2−Time 1)  (2)

wherein Time x represents the new projection acquisition timecorresponding to the new rotation angle; Time 1 represents theprojection acquisition time corresponding to Angle 1; and Time 2represents the projection acquisition time corresponding to Angle 2.

As another example, the angle determination module 440 may determine anew rotation angle between two rotation angles of two projection samplesthat are acquired in two neighboring rotations of the radioactivescanning source 115 based on Formula (3):

Angle(x)=alfa*Angle1+(1−alfa)*(2π+Angle2)  (3)

In some embodiments, if the result of the new rotation angle is greaterthan 2π, the angle determining module 430 may modify the new rotationangle by subtracting 2π from the new rotation angle.

It should be noted that the above description of the processing moduleis merely provided for the purposes of illustration, and not intended tolimit the scope of the present disclosure. For persons having ordinaryskills in the art, multiple variations or modifications may be madeunder the teachings of the present disclosure. However, those variationsand modifications do not depart from the scope of the presentdisclosure. For example, 820 may be omitted in the condition that themodification module 430 performs modification on the original rotationangle.

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure, and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code, etc.) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “unit,” “module,” or “system.” Furthermore, aspects ofthe present disclosure may take the form of a computer program productembodied in one or more computer readable media having computer readableprogram code embodied thereon.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including electro-magnetic, optical, or thelike, or any suitable combination thereof. A computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that may communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device. Program code embodied on acomputer readable signal medium may be transmitted using any appropriatemedium, including wireless, wireline, optical fiber cable, RF, or thelike, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran 2103, Perl, COBOL2102, PHP, ABAP, dynamic programming languages such as Python, Ruby andGroovy, or other programming languages. The program code may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider) or in a cloud computing environment or offered as aservice such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose, and that the appendedclaims are not limited to the disclosed embodiments, but, on thecontrary, are intended to cover modifications and equivalentarrangements that are within the spirit and scope of the disclosedembodiments. For example, although the implementation of variouscomponents described above may be embodied in a hardware device, it mayalso be implemented as a software only solution, for example, aninstallation on an existing server or mobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure aiding in theunderstanding of one or more of the various inventive embodiments. Thismethod of disclosure, however, is not to be interpreted as reflecting anintention that the claimed subject matter requires more features thanare expressly recited in each claim. Rather, inventive embodiments liein less than all features of a single foregoing disclosed embodiment.

In some embodiments, the numbers expressing quantities or propertiesused to describe and claim certain embodiments of the application are tobe understood as being modified in some instances by the term “about,”“approximate,” or “substantially.” For example, “about,” “approximate,”or “substantially” may indicate ±20% variation of the value itdescribes, unless otherwise stated. Accordingly, in some embodiments,the numerical parameters set forth in the written description andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by a particular embodiment. Insome embodiments, the numerical parameters should be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques. Notwithstanding that the numerical ranges andparameters setting forth the broad scope of some embodiments of theapplication are approximations, the numerical values set forth in thespecific examples are reported as precisely as practicable.

Each of the patents, patent applications, publications of patentapplications, and other material, such as articles, books,specifications, publications, documents, things, and/or the like,referenced herein is hereby incorporated herein by this reference in itsentirety for all purposes, excepting any prosecution file historyassociated with same, any of same that is inconsistent with or inconflict with the present document, or any of same that may have alimiting affect as to the broadest scope of the claims now or laterassociated with the present document. By way of example, should there beany inconsistency or conflict between the description, definition,and/or the use of a term associated with any of the incorporatedmaterial and that associated with the present document, the description,definition, and/or the use of the term in the present document shallprevail.

In closing, it is to be understood that the embodiments of theapplication disclosed herein are illustrative of the principles of theembodiments of the application. Other modifications that may be employedmay be within the scope of the application. Thus, by way of example, butnot of limitation, alternative configurations of the embodiments of theapplication may be utilized in accordance with the teachings herein.Accordingly, embodiments of the present application are not limited tothat precisely as shown and described.

1. A system, comprising: one or more storage media comprising a set ofinstructions for analyzing data from a computer tomography (CT) scanner;and one or more processors configured to communicate with the one ormore storage media, wherein when executing the set of instructions, theone or more processors are directed to: obtain a rotation speed of aradioactive scanning source in the CT scanner; obtain a plurality oforiginal projection acquisition times corresponding to a plurality ofprojection samples, the plurality of projection samples being associatedwith rotation of the radioactive scanning source; determine a pluralityof original rotation angles corresponding to the plurality of projectionsamples based on the plurality of original projection acquisition timesand the rotation speed of the radioactive scanning source; and determinea plurality of modified rotation angles corresponding to the pluralityof projection samples by modifying the plurality of original rotationangles.
 2. The system of claim 1, the one or more processors are furtherdirected to: determine one or more interpolation rotation angles basedon the plurality of modified rotation angles.
 3. The system of claim 2,wherein to determine the one or more interpolation rotation angles basedon the plurality of modified rotation angles, the one or more processorsare directed to: obtain one or more view acquisition times associatedwith one or more view samples, the one or more view samples beingassociated with X-rays of the CT scanner; and determine the one or moreinterpolation rotation angles based on the one or more view acquisitiontimes and the plurality of modified rotation angles.
 4. The system ofclaim 1, wherein to determine the plurality of modified rotation anglescorresponding to the plurality of projection samples by modifying theplurality of original rotation angles, the one or more processors aredirected to: obtain a plurality of standard rotation anglescorresponding to the plurality of projection samples; compare theplurality of original rotation angles with the plurality ofcorresponding standard rotation angles, respectively; and modify theplurality of original rotation angles based on the plurality of standardrotation angles and the comparison.
 5. The system of claim 4, wherein toobtain the plurality of standard rotation angles corresponding to theplurality of projection samples, the one or more processors are directedto: obtain a sample number of the plurality of projection samples;determine, based on the sample number of the plurality of projectionsamples, a standard angle difference corresponding to any twoneighboring projection samples arranged in time order; and determine theplurality of standard rotation angles based on the standard angledifference.
 6. The system of claim 4, wherein to obtain the plurality ofstandard rotation angles corresponding to the plurality of projectionsamples, the one or more processors are directed to: obtain a samplenumber of the plurality of projection samples; determine, based on thesample number of the plurality of projection samples and the rotationspeed of the radioactive scanning source, a standard time differencecorresponding to any two neighboring projection samples arranged in timeorder; determine a standard angle difference corresponding to any twoneighboring projection samples arranged in time order based on therotation speed of the radioactive scanning source and the standard timedifference; and determine the plurality of standard rotation anglesbased on the standard angle difference.
 7. The system of claim 1,wherein to determine the plurality of modified rotation anglescorresponding to the plurality of projection samples by modifying theplurality of original rotation angles, the one or more processors aredirected to: obtain a standard angle difference value corresponding toany two neighboring projection samples of the plurality of projectionsamples arranged in time order; determine a plurality of originaldifference values each of which corresponds to two neighboring originalrotation angles of the plurality of original rotation angles arrangingin order of time; compare the plurality of the original differencevalues with the standard difference value, respectively; modify theplurality of original difference values based on the standard differencevalue and the comparison; and determine the plurality of modifiedrotation angles based on the plurality of modified difference values. 8.A system, comprising: one or more storage media comprising a set ofinstructions for analyzing data from a computer tomography (CT) scanner;and one or more processors configured to communicate with the one ormore storage media, wherein when executing the set of instructions, theone or more processors are directed to: obtain a rotation speed of aradioactive scanning source in the CT scanner; obtain a plurality oforiginal projection acquisition times corresponding to the plurality ofprojection samples, the plurality of projection samples being associatedwith rotation of the radioactive scanning source; determine a pluralityof modified projection acquisition times corresponding to the pluralityof projection samples by modifying the plurality of original projectionacquisition times; and determine a plurality of modified rotation anglescorresponding to the plurality of projection samples based on therotation speed of the radioactive scanning source and the plurality ofmodified projection acquisition times.
 9. The system of claim 8, the oneor more processors are further directed to: determine one or moreinterpolation rotation angles based on the plurality of modifiedrotation angles.
 10. The system of claim 9, wherein to determine the oneor more interpolation rotation angles based on the plurality of modifiedrotation angles, the one or more processors are directed to: obtain oneor more view acquisition times associated with one or more view samples,the one or more view samples being associated with X-rays of the CTscanner; and determine the one or more interpolation rotation anglesbased on the one or more view acquisition times and the plurality ofmodified rotation angles.
 11. The system of claim 8, wherein todetermine the plurality of modified projection acquisition times, theone or more processors are directed to: obtain a plurality of standardprojection acquisition times corresponding to the plurality ofprojection samples; compare the plurality of original projectionacquisition times with the plurality of corresponding standardprojection acquisition times, respectively; and modify the plurality oforiginal projection acquisition times based on the plurality of standardprojection acquisition times and the comparison.
 12. The system of claim11, wherein to obtain the plurality of standard projection acquisitiontimes corresponding to the plurality of projection samples, the one ormore processors are directed to: obtain a sample number of the pluralityof projection samples; determine a standard time difference valuecorresponding to any two neighboring projection samples of the pluralityof projection samples arranged in time order based on the sample numberof the plurality of projection samples and the rotation speed of theradioactive scanning source; and determine the plurality of standardprojection acquisition times based on the standard time differencevalue.
 13. The system of claim 8, wherein to determine the plurality ofmodified projection acquisition times, the one or more processors aredirected to: obtain a standard time difference value corresponding toany two neighboring projection samples of the plurality of projectionsamples arranged in time order; determine a plurality of original timedifference values each of which corresponds to two neighbor originalprojection acquisition times of the plurality of original projectionacquisition times; compare the plurality of original time differencevalues with the standard time difference value, respectively; modify theplurality of original time difference values based on the standard timedifference value and the comparison; and determine the plurality ofmodified projection acquisition times based on the plurality of modifiedtime difference values.
 14. A method implemented on a computing devicehaving one or more processors and one or more storage devices, themethod comprising: obtaining a rotation speed of a radioactive scanningsource in a CT scanner; obtaining a plurality of original projectionacquisition times corresponding to a plurality of projection samples,the plurality of projection samples being associated with rotation ofthe radioactive scanning source in the CT scanner; determining aplurality of original rotation angles corresponding to the plurality ofprojection samples based on the plurality of original projectionacquisition times and the rotation speed of the radioactive scanningsource; and determining a plurality of modified rotation anglescorresponding to the plurality of projection samples by modifying theplurality of original rotation angles.
 15. The method of claim 14, themethod further comprising: determining one or more interpolationrotation angles based on the plurality of modified rotation angles. 16.The method of claim 15, wherein the determining of the one or moreinterpolation rotation angles based on the plurality of modifiedrotation angles comprises: obtaining one or more view acquisition timesassociated with one or more view samples, the one or more view samplesbeing associated with X-rays of the CT scanner; and determining the oneor more interpolation rotation angles based on the one or more viewacquisition times and the plurality of modified rotation angles.
 17. Themethod of claim 14, wherein the determining of the plurality of modifiedrotation angles corresponding to the plurality of projection samples bymodifying the plurality of original rotation angles comprises: obtaininga plurality of standard rotation angles corresponding to the pluralityof projection samples; comparing the plurality of original rotationangles with the plurality of corresponding standard rotation angles,respectively; and modifying the plurality of original rotation anglesbased on the plurality of standard rotation angles and the comparison.18. The method of claim 17, wherein the obtaining of the plurality ofstandard rotation angles corresponding to the plurality of projectionsamples comprises: obtaining a sample number of the plurality ofprojection samples; determining, based on the sample number of theplurality of projection samples, a standard angle differencecorresponding to any two neighboring projection samples arranged in timeorder; and determining the plurality of standard rotation angles basedon the standard angle difference.
 19. The method of claim 17, whereinthe obtaining of the plurality of standard rotation angles correspondingto the plurality of projection samples comprises: obtaining a samplenumber of the plurality of projection samples; determining, based on thesample number of the plurality of projection samples and the rotationspeed of the radioactive scanning source, a standard time differencecorresponding to any two neighboring projection samples arranged in timeorder; determining a standard angle difference corresponding to any twoneighboring projection samples arranged in time order based on therotation speed of the radioactive scanning source and the standard timedifference; and determining the plurality of standard rotation anglesbased on the standard angle difference.
 20. The method of claim 14,wherein the determining of the plurality of modified rotation anglescorresponding to the plurality of projection samples by modifying theplurality of original rotation angles comprises: obtaining a standardangle difference value corresponding to any two neighboring projectionsamples of the plurality of projection samples arranged in time order;determining a plurality of original difference values each of whichcorresponds to two neighbor original rotation angles of the plurality oforiginal rotation angles arranging in order of time; comparing theplurality of the original difference values with the standard differencevalue, respectively; modifying the plurality of original differencevalues based on the standard difference value and the comparison; anddetermining the plurality of modified rotation angles based on theplurality of modified difference values. 21-30. (canceled)